METHOD OF CREATING QoS FLOW FOR TIME SYNCHRONIZATION PROTOCOL IN WIRELESS COMMUNICATION NETWORK

ABSTRACT

Provided is a method of creating a QoS flow for a time synchronization protocol in a wireless communication network. A method of creating a QoS flow for a time synchronization protocol in a wireless communication network includes: receiving, by a Session Management Function (SMF), the PTP profile information from the UE, together with at least one of a DNN, a S-NSSAI information and a session ID for a Time Sensitive Communication (TSC) service; setting, by the SMF, a PCCrule of the QoS flow for the time synchronization protocol; providing, by the SMF, the QoS flow and a SDF filter information for the QoS flow to a User Plane Function (UPF); and providing, by the SMF, the QoS flow and a QoS rule filter to an Access and Mobility Management Function (AMF).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication No. 10-2020-0123095 filed in the Korean IntellectualProperty Office on Sep. 23, 2020, and Korean Patent Application No.10-2021-0124839 filed in the Korean Intellectual Property Office on Sep.17, 2021, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure relates to a method of creating a QoS flow foreffectively delivering a time synchronization protocol for supporting aTime Sensitive Communication (TSC) in a 5G System (5GS).

2. Description of Related Art

A 5GS supports interworking with a Time Sensitive Networking (TSN) tosupport a TSC. In a TSC, time synchronization of devices participatingin the TSC is premised, time synchronization is performed using a timesynchronization protocol, and 5GS acting as a virtual bridge for the TSCneeds to effectively communicate the time synchronization protocol.However, since the time synchronization protocol corresponds to usertraffic in the 5GS virtual bridge, there is a need for a method capableof efficiently delivering the time synchronization protocol by creatinga QoS flow.

In a 5G, one or more QoS flows are supported for a Protocol Data Unit(PDU) session, and each QoS flow may have different traffic processingcharacteristics. If the QoS flow for delivering the time synchronizationprotocol does not satisfy the QoS level required by the timesynchronization protocol, the time synchronization quality may not besatisfactory. The conventional QoS flow generation in a 5G does notautomatically reflect the characteristics for time synchronizationprotocol delivery, so the effective operation of the timesynchronization protocol cannot be guaranteed.

If the delay occurring in the delivery of the time synchronizationprotocol is above a certain level or the deviation of the delayoccurring in the delivery of the time synchronization protocol becomeslarge, it is difficult to guarantee the operation of the timesynchronization protocol. The time synchronization protocol has aprinciple of operation using the mean path delay between a master clockand a slave clock for time synchronization, if the 5GS virtual bridge ona path of the time synchronization protocol does not guarantee properQoS, the average path delay will be out of the appropriate level or thedeviation will become too large, so that the performance of the timesynchronization protocol cannot be guaranteed.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the disclosure, andtherefore it may contain information that does not form the prior artthat is already known in this country to a person of ordinary skill inthe art.

SUMMARY OF THE DISCLOSURE

The present disclosure has been made in an effort to provide a method ofcreating a QoS flow for a time synchronization protocol in a wirelesscommunication network having advantages of creating a QoS flow that cansatisfy the QoS required by the time synchronization protocol when amaster clock and slave clocks for a TSC in 5GS perform synchronizationusing the time synchronization protocol.

An example embodiment of the present disclosure provides a method ofcreating a QoS flow for a time synchronization protocol in a wirelesscommunication network, the method may include: receiving, by a SessionManagement Function (SMF), a PTP profile information from a UE, togetherwith at least one of a DNN, a S-NSSAI information and a session ID for aTime Sensitive Communication (TSC) service; setting, by the SMF, aPCCrule of the QoS flow for the time synchronization protocol;providing, by the SMF, the QoS flow and an SDF filter information forthe QoS flow to a User Plane Function (UPF); and providing, by the SMF,the QoS flow and a QoS rule filter to an Access and Mobility ManagementFunction (AMF).

According to an embodiment of the present disclosure, wherein: thesetting, by the SMF, a PCCrule of the QoS flow for the timesynchronization protocol, may include: using a preset PCCrule, setting,by the SMF, the PCCrule and the QoS flow for the time synchronizationprotocol.

According to an embodiment of the present disclosure, wherein: thesetting, by the SMF, a PCCrule of the QoS flow for the timesynchronization protocol may include: requesting, by the SMF, a PolicyControl Function (PCF) to set a PCCrule; receiving the set PCCrule fromthe PCF; and using the received PCCrule, setting, by the SMF, thePCCrule and the QoS flow for the time synchronization protocol.

According to an embodiment of the present disclosure, wherein: therequesting, by the SMF, a PCF to set a PCCrule, may include:transmitting, by the SMF, the PTP profile information provided from theUE to the PCF together with the DNN, the S-NSSAI information and thesession ID.

According to an embodiment of the present disclosure, wherein: the PTPprofile information may be transmitted through an Announce message.

According to an embodiment of the present disclosure, wherein: the PTPprofile information may include: at least one of a selection informationfor one-step or two-step, an information on a method to be used as apath delay mechanism and an information on a method to be used as atransport mechanism, an information on whether to use multicast orunicast, its address, and an information on the period of each PTPmessage.

According to an embodiment of the present disclosure, wherein: the QoSflow may include: at least one of Packet Delay Budget (PDB), Priority,Allocation and Retention Priority (ARP), and Guaranteed Flow Bit Rate(GFBR).

According to an embodiment of the present disclosure, wherein: the SDFfilter and the QoS rule filter may include: at least one of a multicastaddress of an Ethernet for the time synchronization protocol, anethertype of the Ethernet for the time synchronization protocol, amulticast address of IP for time synchronization protocol and a port ofUDP for time synchronization protocol

According to an embodiment of the present disclosure, wherein: when aQoS requirement of a PTP profile information provided from the UE islower than a QoS requirement for the preset PTP profile, the QoS flowmay be created based on the QoS requirement for the preset PTP profile.

Another embodiment of the present disclosure provides a network entityof a 5G system operating as a TSN bridge, the network entity mayinclude: a network interface; and a processor configured to: receive aPTP profile information from a UE, together with at least one of a DNN,a S-NSSAI information and a session ID for a TSC service; setting aPCCrule of the QoS flow for the time synchronization protocol; providingthe QoS flow and an SDF filter information for the QoS flow to a UPF;and providing the QoS flow and a QoS rule filter to an AMF.

Another embodiment of the present disclosure provides a method ofcreating a QoS flow for a time synchronization protocol in a wirelesscommunication network, the method may include: receiving, by a SMF, asession modification request comprising ReQQoS, which is a QoS requiredfor the QoS flow specified by PktFltr, which is Packet Filter for thetime synchronization message, from a UE; setting, by the SMF, a sessionpolicy; requesting, by the SMF, a QoS flow modification for the sessionto the UPF; and providing, by the SMF, a QoS flow modificationinformation for the session to an AMF.

According to an embodiment of the present disclosure, wherein: thesetting, by the SMF, a session policy, may include: using a presetPCCrule, setting, by the SMF, the session policy.

According to an embodiment of the present disclosure, wherein: thesetting, by the SMF, a session policy, may include: requesting, by theSMF, the PCF to modify the PCCrule; receiving the modified PCCrule fromthe PCF; and using the received PCCrule, setting, by the SMF, thesession policy.

According to an embodiment of the present disclosure, the method furtherincludes: when the ReQQoS and the PTP profile from the UE are higherthan a QoS requirement of a PTP profile currently used in a TSN domainto which the UE belongs, performing a session modification for thesessions of other UEs using a QoS flow based on the PTP profilecurrently used in the TSN domain.

According to an embodiment of the present disclosure, wherein: the PTPprofile information may include: at least one of a selection informationfor one-step or two-step, an information on a method to be used as apath delay mechanism and an information on a method to be used as atransport mechanism, an information on whether to use multicast orunicast, its address, and an information on the period of each PTPmessage.

Another embodiment of the present disclosure provides a network entityof a 5G system operating as a TSN bridge, the network entity mayinclude: a network interface; and a processor configured to: receive asession modification request comprising ReQQoS, which is a QoS requiredfor the QoS flow specified by PktFltr, which is Packet Filter for thetime synchronization message, from a UE; setting a session policy;requesting a QoS flow modification for the session to the UPF; andproviding a QoS flow modification information for the session to an AMF.

Another embodiment of the present disclosure provides a method ofcreating a QoS flow for a time synchronization protocol in a wirelesscommunication network, the method may include: receiving, by a SMF, atleast one of a DNN, a S-NSSAI information and a session ID for a TSCservice not including a PTP profile information from a UE; setting, bythe SMF, a PCCrule of the QoS flow for the time synchronization protocolusing a PTP profile information stored in the SMF; providing, by theSMF, the QoS flow and an SDF filter information for the QoS flow to aUPF; and providing, by the SMF, the QoS flow and a QoS rule filter to anAMF.

Another embodiment of the present disclosure provides, a network entityof a 5G system operating as a TSN bridge, the network entity mayinclude: a network interface; and a processor configured to: receive atleast one of a DNN, a S-NSSAI information and a session ID for a TSCservice not including a PTP profile information from a UE; setting aPCCrule of the QoS flow for the time synchronization protocol using aPTP profile information stored in the network entity; providing, by thenetwork, the PCCrule to the SMF; providing, by the SMF, the QoS flow andan SDF filter information for the QoS flow to a UPF; and providing, bythe SMF, the QoS flow and a QoS rule filter to an AMF.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a TSN bridge according to an embodiment of thepresent disclosure.

FIG. 2 illustrates a TSN bridge according to an embodiment of thepresent disclosure.

FIG. 3 illustrates an example of a master clock and a slave clock when atime synchronization protocol according to an embodiment of the presentdisclosure is applied.

FIG. 4 and FIG. 5 illustrate an example in which a TSN bridge isconfigured with 5GS according to an embodiment of the presentdisclosure.

FIG. 6 illustrates a PDU session and a QoS flow in 5GS according to anembodiment of the present disclosure.

FIG. 7 illustrates properties of a QoS flow used in 5GS according to anembodiment of the present disclosure.

FIG. 8 illustrates a delay from a TSN GM to a TSN bridge/end stationaccording to an embodiment of the present disclosure.

FIG. 9 illustrates a delay when a 5G network operates as a TSN bridgeaccording to an embodiment of the present disclosure.

FIG. 10 illustrates an example of a PTP protocol according to anembodiment of the present disclosure.

FIG. 11 illustrates an example of an Ethernet frame according to anembodiment of the present disclosure.

FIG. 12 illustrates an example of a UDP/IPv4 header according to anembodiment of the present disclosure.

FIG. 13 illustrates an example of a PTP profile according to anembodiment of the present disclosure.

FIG. 14 illustrates obtaining a time synchronization protocol profileaccording to an embodiment of the present disclosure.

FIG. 15 illustrates a relationship between QoS requirements of a masterclock profile according to an embodiment of the present disclosure.

FIG. 16 illustrates a procedure for setting a QoS flow for a timesynchronization protocol when establishing a PDU session according to anembodiment of the present disclosure.

FIG. 17 illustrates a procedure for modifying a QoS flow through a PDUsession modification procedure from a UE according to an embodiment ofthe present disclosure.

FIG. 18 illustrates a procedure for modifying a QoS flow for an existingtime synchronization protocol of another UE using a PDU sessionmodification procedure according to an embodiment of the presentdisclosure.

FIG. 19 illustrates a procedure for setting a QoS flow for a PDU sessiontime synchronization protocol according to an embodiment of the presentdisclosure.

FIG. 20 is a block diagram illustrating a computing device according toan embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the accompanying drawings so that those ofordinary skill in the art may easily implement the present disclosure.However, the present disclosure may be implemented in various differentways and is not limited to the embodiments described herein. In thedrawings, parts irrelevant to the description are omitted in order toclearly describe the present disclosure, and like reference numerals areassigned to like elements throughout the specification.

Throughout the specification and claims, unless explicitly described tothe contrary, the word “comprise”, and variations such as “comprises” or“comprising”, will be understood to imply the inclusion of statedelements but not the exclusion of any other elements. In addition, termssuch as “ . . . unit”, “ . . . group”, and “module” described in thespecification mean a unit that processes at least one function oroperation, and it can be implemented as hardware or software or acombination of hardware and software.

FIG. 1 illustrates a TSN bridge according to an embodiment of thepresent disclosure.

Referring to FIG. 1, the illustrated is an example in which the bridgesB1, B2, . . . , Bn are connected between the TSC stations S1 and S2 ofboth ends. One of the stations S1 and S2 may operate as a master clockand the other may operate as a slave clock, the master clock may providea time synchronization message, and the slave clock may synchronize itsown time with the master clock by receiving the time synchronizationmessage provided from the master clock. Unlike the one shown in FIG. 1,the bridges B1, B2, . . . , Bn between the master clock and the slaveclock can be configured in various types of networks, and in anyconfiguration, accurate time synchronization can be guaranteed only whena certain level of communication quality is guaranteed.

FIG. 2 illustrates a TSN bridge according to an embodiment of thepresent disclosure.

Referring to FIG. 2, in the case of multiple clocks for a TSC, theillustrated is an example in which the bridges B1, B2, . . . , Bn areconnected between the TSC stations S1 and S4 of both ends. When thestation S1 is the master clock and the stations S2, S3, and S4 are theslave clocks, the stations S2, S3, and S4 synchronize with the stationS1.

When both the station S1 and the station S2 are the master clocks, thestation S1 is selected as the master clock through the Best Master ClockAlgorithm (BMCA) between them, and the station S2 does not perform therole of the master clock. In some embodiments of the present disclosure,the master clock may mean both the station S1 and the station S2, oralternatively, only the station S1 after performing BMCA.

The best master clock within one TSC domain becomes the GrandMasterClock, and other clocks can operate as a master clock themselves bysynchronizing clocks from the GrandMaster Clock.

FIG. 3 illustrates an example of a master clock and a slave clock when atime synchronization protocol according to an embodiment of the presentdisclosure is applied.

Referring to FIG. 3, when two master clocks GM1 and GM2 are applied,BMCA is applied between them to operate the master clock GM1 as theactive master clock and the master clock GM2 as a passive master clockthat does not act as a master. A boundary clock BC and a Slave clock 1may be synchronized from the master clock GM1 via a first transparentclock TC1, a Slave clock 2 may be synchronized from the boundary clockBC, and a Slave clock 3 may be synchronized via a second transparentclock TC2. That is, the boundary clock BC may receive a timesynchronization message from the master clock, become the master andprovide the time synchronization message to the lower clocks again, andthe transparent clock including the first transparent clock TC1 and thesecond transparent clock TC2 may transparently transmit the timesynchronization protocol between the master clock and the slave clock.The transparent clock may operate in an end-to-end (EE) mode or apeer-to-peer (PP) mode, which will be described later with reference toFIG. 8 and FIG. 10.

FIG. 4 and FIG. 5 illustrate an example in which a TSN bridge isconfigured with 5GS according to an embodiment of the presentdisclosure.

Referring to FIG. 4, 5GS may be applied to any of the bridges B1, B2, .. . , Bn of FIG. 1, and the 5GS bridge 10 may include a user equipment(UE) 100, a User Plane Function (UPF) 104 and Radio Access Network (RAN)108, and the like.

Referring to FIG. 5, the illustrated is an example of a controlinterface of 5G TSC. When a 5G network 10 is inserted as a TSN bridge inthe middle of the TSN system, translators for TSN may be required onboth sides of the 5G network 10. In FIG. 5, the 5G network 10 mayoperate as a bridge for connecting a TSN bridge/end station 20 to theTSN system 30. The TSN system 30 may be referred to as a DN or a TSN-DN.The 5G network 10 may transmit a time synchronization information of theTSN GM 32 in the TSN-DN 30 to the TSN bridge/end station 20.

The CNC/CUC 34 may collect a topology-related information andrequirements of the TSN end stations 36 in the TSN system 30, and defineand command the operating characteristics of the TSN bridge and TSN endstations.

The Application Function (AF) 110 may provide the topology-relatedinformation of the 5G network 10 and the TSN bridge/end station 20connected through the 5G network 10 to the CNC/CUC 34, and receive acommand for an operation method of the 5G network 10 and the TSNbridge/end station 20 connected through the 5G network 10 from theCNC/CUC 34. AF can be replaced by the term TSN AF, which may receive therequirements for processing time sensitive data for a specific streamvia a control protocol from the CNC/CUC 34 and deliver them via a PolicyControl Function (PCF) 112. The PCF 112 may set a PCCrule based on theinformation received from the AF 100. Requirements for processing a timesensitive data may include a stream identifier (ID), a bandwidth, amaximum frame size, a frame period, and the like, for a particularstream. The AF 110 and the PCF 112 may communicate directly orcommunicate through a Network Exposure Function (NEF) 120 according tothe network topology.

The PCF 112 may provide the topology related information and PTPrequirements of the 5G network 10 and the TSN bridge/end station 20connected through the 5G network 10, received from the SessionManagement Function (SMF) 114, to the AF 110; may determine whether theUE 100 may be serviced with the requirements for processing the timesensitive service information from the AF 110; and may inform the SMF114 of the determined result. The UDM 118 may manage a subscriptioninformation including a time sensitive service subscribed by the UE 100in the 5G network 10, and provide it to the Access and MobilityManagement Function (AMF) 116/SMF 114. The AMF 116 may enable the UE 100to access the 5G network 10, and the AMF 115 may enable the UE 100 toestablish a session for the TSC in the 5G network 10.

A Network TSN Translator (NW-TT) 106 may perform conversion between the5G network 10 and the TSN system 30 on TSN data frames. The NW-TT 106may exist within the UPF 104 or may exist independently outside the UPF104. Since the 5G network 10 employs a packet processing method higherthan the IP layer, and the TSN system 30 employs a frame processingmethod in the data link layer, the NW-TT 106 may perform conversion fordifferent layers.

The UE 100 may be connected to the TSN bridge/end station 20 through aDevice Side TSN Translator (DS-TT) 102. The DS-TT 102 may performconversion between the traffic transmitted from the TSN system 30 andthe traffic transmitted to the TSN system for the UE 100 belonging tothe 5G network 10, and further perform conversion to control. The DS-TT102 may have a role similar to AF 110 and NW-TT 106. The DS-TT 102 mayexist inside the UE 100, or may exist independently outside the UE 100.

A Radio Access Network (RAN) 108 may perform radio access to the movingUE 100. The UPF 104 may perform processing on user data, and may serveas an anchor of the UE 100 for the TSN system 30 when the user moves toa range where the UPF 104 changes. Here, one or more UPFs 104 may beadded between the anchor UPF 104 and the RAN 108. The NEF 120 may informthe function of the 5G network 10 to the TSN system 30, and the TSNsystem 30 may use the 5G network 10 based on this.

The 5G network 10 is internally time-synchronized with the 5G clock tosupport a TSC. The TSN system 30 and the TSN bridge/end station 20 mustbe time-synchronized with the TSN GM 32. For this purpose, PTP or thelike may be used. When the time sensitive information received from theTSN system 30 is transmitted to the TSN bridge/end station 20, the timesensitive information is corrected by measuring a residence timerequired to transit the 5G network 10, and thereby synchronization withthe TSN GM may be performed. In embodiments of the present disclosure,the performance of the time synchronization protocol is ensured bycreating a QoS flow for the time synchronization protocol so that the 5Gresidence time is within a certain amount of time and the deviation isalso within a certain range.

Here, the synchronized time may be expressed in including year, month,day, hour, minute, second, millisecond, microsecond, and nanosecond.

FIG. 6 illustrates a PDU session and a QoS flow in 5GS according to anembodiment of the present disclosure.

Referring to FIG. 6, a PDU session may generally include uplink (UL) anddownlink (DL) data radio bearer (DRB) and GTP-U tunnels, and the GTP-Utunnel may include an N3 tunnel and an N9 tunnel. When there is nointermediate UPF between the RAN and the anchor UPF connected to the TSNsystem, only the N3 tunnel exists, alternatively, when there is anintermediate UPF, an N9 tunnel exists between the intermediate UPF andthe anchor UPF. The QoS rules and SDF filters can be used to map userdata in the form of Ethernet frames or IP packets to QoS flows.

One service data flow has one or more QoS flows, and in this case, QoSflows can be applied independently or equally for each uplink/downlink(UL/DL).

FIG. 7 illustrates properties of a QoS flow used in 5GS according to anembodiment of the present disclosure.

Referring to FIG. 7, a QoS Flow Identifier (QFI) is an identifierindicating a QoS flow, and is a unique value within a PDU session.Packet flows with the same QFI may receive the same QoS processing. AQoS flow represented by one QFI may be defined with various parameters.

A 5G QoS Identifier (5QI) is an identifier for a QoS flow processingmethod predetermined in 5G, and it is possible to change some operationcharacteristics for 5QI, and to define a new 5QI.

In addition, a QoS flow may be defined with properties such as Priorityindicating a priority, Packet Delay Budget (PDB) indicating a delay,CN_PDB indicating a delay of the core network (see FIG. 9), Packet ErrorRate (PER) indicating allowable packet error rate, Allocation andRetention Priority (ARP) indicating a pre-emption capability and apre-emption vulnerability, Maximum Data Burst Volume (MDBV) indicatingthe instantaneous maximum transmission amount, Averaging Windowindicating the unit time for calculating the transmission rate ofGFBR/MFBR, Reflective QoS Attribute (RQA) indicating an informationrelated to Reflective QoS application, Notification Control (NC)indicating whether to report when GFBR is not satisfied, Guaranteed FlowBit Rate (GFBR) indicating a guaranteed transmission rate, Maximum FlowBit Rate (MFBR) indicating a maximum transmission rate, and MaximumPacket Loss Rate (MPLR) indicating the maximum packet loss rate. Here,GFBR, MFBR, and MPLR can be set separately for uplink/downstream. Insome embodiments of the present disclosure, only specific parameters maybe set without setting all of the QoS flow attribute values listedabove, and no separate control may be performed on unset parameters.

Uplink/downlink QoS flows may be set with the same characteristics orset with different characteristics each other.

FIG. 8 illustrates a delay from a TSN GM to a TSN bridge/end stationaccording to an embodiment of the present disclosure.

Referring to FIG. 8, delays from the TSN GM to the TSN Bridge/Endstations are shown for each section, and the delay when the bridge Boperates as the transparent clock TC of the PTP is shown. When thetransparent clock TC operates in the end-to-end mode, the end-to-enddelay is measured between the master clock MC and the slave clock SC,while when the transparent clock TC operates in the peer-to-peer mode,the peer-to-peer delay between the master clock MC and the slave clockSC, and the transparent clock TC delay may be measured and used. Thetransparent clock TC can be corrected by measuring the residence time inthe bridge (B) when the time synchronization protocol signal from themaster clock is transmitted, and the residence time and deviation mustbe within a certain range.

The 5GS may operate as a transparent clock to TSN.

FIG. 9 illustrates a delay when a 5G network operates as a TSN bridgeaccording to an embodiment of the present disclosure.

Referring to FIG. 9, the delay from the UPF 104/NW-TT 106 to the UE 100in the 5G network 10 is a Packet Delay Bound (PDB), of which the delayfrom the UPF 104/NW-TT 106 to the RAN 108 is CN_PDB, and the delay fromthe RAN 108 to the UE 100 is RAN PDB. The sum of RAN PDB and CN_PDB isthe PDB of the 5G network 10. The transfer time from the DS-TT 102 tothe UE 100 is the UE-DSTT residence time, and the sum of the UE-DSTTresidence time and the PDB is the 5G bridge residence time.

In the case of the TSN system A 20 a, 30 a of FIG. 9, the master clocksMC are shown as A1 and A2, respectively, but only one of them operatesas the best master clock through the BMCA, and the delay in this casetakes as much as the 5G bridge residence time.

In the case of the TSN system B 20 b, 20 c, 30 b of FIG. 9, the delaywhen B1 operates as the best master clock through BMCA among the masterclocks B1, B2, and B3 takes as much as the 5G bridge residence time.When B2 or B3 operates as the best master clock, the delay when the timesynchronization protocol is delivered to the TSN end station B1 takes asmuch as the 5G bridge residence time, but the delay when the timesynchronization protocol is delivered from the GM, which is B2 or B3, tothe TSN end station B3 or the TSN end station B2 becomes (2*(5G bridgeresidence time)−UPF_processingdelay). Here, UPF_processingdelay is apacket processing delay in the UPF 104/NW-TT 106 and is a value includedin the calculation of the CN_PDB.

FIG. 10 illustrates an example of a PTP protocol according to anembodiment of the present disclosure.

Referring to FIG. 10, OC-M is an ordinary clock operating as a master,and OC-S is an ordinary clock operating as a slave. BC is a boundaryclock, TC (EE) is a transparent clock operating in the end-to-end mode,and TC (PP) is a transparent clock operating in the peer-to-peer mode.Usually a clock is a master clock or a slave clock with only one port.The boundary clock is a clock with more than one port, one port operatesas a slave to the upper master and the other ports operate as masters.The boundary clock synchronizes with the upper master as a slave andsupplies the synchronized time to other slaves as a master. One portoperates as a slave to the upper master, and the other ports operate asmasters. The transparent clock is a clock with more than one port and,by measuring the residence time of a PTP event message passing throughthe transparent clock and providing the transit time information usingthe PTP message, the clocks that receive the PTP message through thetransparent clock may compensate for the time spent passing through thetransparent clock. The transparent clock provides the end-to-end modeand the peer-to-peer mode. The transparent clock in end-to-end modeprovides a transit time of the transparent clock for an end-to-end delaymeasurement between the master and the slave. The transparent clock inthe peer-to-peer mode measures the peer-to-peer delay between the uppermaster and the transparent clock and provides it in addition to thetransit time of the transparent clock. At this time, the slave below thetransparent clock measures the peer-to-peer delay between thetransparent clock and itself and uses it to compensate for its own time.

The Sync message is a packet that periodically transmits the referencetime from the master to the slave, in one-step PTP, the time at whichthe Sync message is transmitted is recorded in the Sync message. TheFollowUp message records the transmission time of the Sync message intwo-step PTP and delivers it to the slave. FollowUp message is deliveredat the same period as Sync message.

DelayReq/DelayResp messages are used to calculate one-way delay, and thetime when the master receives the DelayReq message from the slave isrecorded in the DelayResp message and delivered back to the slave. Theseare delivered in the same period as the Sync message.PDelayReq/PDelayResp/PDelayRespFollowUp messages are used to measure thelink delay between the upper master and the transparent clock andbetween the transparent clock and the lower slave when the peer-to-peertransparent clock method is used. The PDelayRespFollowUp messagetransmits the time when the PDelayResp message is sent when two-step PTPis applied. An Announce message is a message that periodically deliversthe PTP attribute of each master to determine the GM, and the GM isdetermined using the BMCA based on the PTP attribute of the Announcemessage. BMCA organizes clocks into a hierarchical structure and ensuresthat the slave clock uses the most accurate clock available on thenetwork. Ports of the ordinary clock and the boundary clock that are notslave-only transmit the Announce message including attributes includingclock priority and quality, and each clock in the network select thebest clock to synchronize using attributes received from the BMCA andthe Announce message, and determines the PTP state of each port as M, S,and P. M corresponds to a master and is a port for sending thesynchronization information, S corresponds to a slave and is a port forreceiving the synchronization information, and P corresponds to apassive and is port that neither sends nor receives the synchronizationinformation. A Management message is used for network management such asmonitoring, setting, and management of the PTP system. A Signalingmessage are used for a non-time-critical communication such as servicenegotiation between clocks.

PTP can operate in one-step or two-step. One-step is a method in whichthe time when the Sync message is transmitted from the master isdirectly recorded in the Sync message. Similarly, in one step, the timeis directly recorded in the PDelayResp message, but in two step, thetime at which the PDelayResp message is transmitted is recorded in thePDelayRespFollowUp message and delivered.

The PTP Sync, FollowUp, DelayReq, DelayResp, PDelayReq, PDelayResp, andPDelayRespFollowUp messages of FIG. 10 are transmitted periodically.Also, the Announce message is transmitted periodically. For clarity ofexplanation, the explanation is mainly based on the Sync message.

The syncInterval indicating the period of the PTP Sync message isexpressed as an exponent of 2 using LogSyncInterval, ifLogSyncInterval=0, syncInterval is 1 second, if LogSyncInterval=1,syncInterval is 2 seconds, if LogSyncInterval=−1, syncInterval is ½second, if LogSyncInterval=−5, syncInterval is 1/32 second, and ifLogSyncInterval=−7, syncInterval is 1/128 second. SyncInterval isdetermined according to the accuracy of the local clock of the endstation and the clock accuracy required by the application of the endstation.

The amount of data required for PTP may vary depending on the appliedPTP profile. It is affected by various factors such as the type oftransport used such as Ethernet/IPv4/IPv6, one-step/two-step PTP method,the transmission period of each message, and the size of the variablemessage body. Here, an example of calculation is shown based on the caseof transmitting only Sync messages with LogSyncInterval=−7 throughEthernet in one-step PTP method. One-step PTP's Sync message is 118bytes including Ethernet overhead, which is 944 bits. If it istransmitted at 128 times/sec, it will be about 120 kbps. For the slaveclocks receiving the time synchronization protocol message from anothermaster clock, in FIG. 9, when B1 provides the time synchronizationmessages to B2 and B3, B2 and B3 each need 120 kbps, but in case B2provides the time synchronization message to B1 and B3 as a master, B2needs a higher transmission rate for DelayReq/Resp from B3.

As described above, the guaranteed flow bit rate of 5G QoS required forPTP protocol transmission is determined by considering various factorssuch as the type of transport, one-step/two-step PTP method, and theend-to-end/peer-to-peer path delay mechanism, the Sync message, theDelayReq/Resp message, PDelayReq/Resp message, the transmission periodof the Announce message, the size of the variable message, and thenumber of connected slave clocks, etc.

The bridge delay (residence time) required to transmit the PTP messageis affected by the transmission period of the Sync message. For example,the bridge delay should be greater than or equal to 0.7*syncInterval andless than or equal to 1.3*syncInterval. Here, an example of calculatingbased on the case of LogSyncInterval=−7 is shown. The syncIntervalbecomes 1/128 second, and the requirement of the bridge delay is 5.5 msor more and 10 ms or less. The 5G QoS PDB required for PTP protocoltransmission is determined in consideration of the Sync message cycle,and a QoS flow that satisfies this transmission delay is set.

An acceptable error rate in transmitting the PTP message is affected bythe accuracy of the local clock of the end station and the clockaccuracy required by the application of the end station. The local clockof the end station receives the Sync message and synchronizes to the GM,and an error occurs after a certain period of time passes, and the erroris overcome by receiving the next Sync message. That is, the tolerabledegree of error for the Sync messages from GM is determined at the timeof designing the TSC system.

FIG. 11 illustrates an example of an Ethernet frame according to anembodiment of the present disclosure.

Referring to FIG. 11, when the PTP is transmitted through Ethernet, ifEthernet preamble, Start of Frame Delimiter (SFD), the destination MACaddress, the source MAC address, 802.1Q Tag, EtherType, PTP-Data, FrameCheck Sequence (FCS), Inter Frame Gap (IFG) are all added up, the PTPsync message is 76 bytes in the case of configuring the PTP in two stepsand 118 bytes in the case of configuring the PTP in one step.

The PTP message format included in the payload of Ethernet consists of amessage header 34 bytes and a variable message body, but in the case ofthe Sync message, the message body is 10 bytes or 52 bytes, which is 44bytes or 86 bytes in total. When configuring the PTP in one-step, itbecomes 44 bytes, and when configuring the PTP in two-step, it becomes86 bytes. A QoS flow that satisfies the transmission delay is set, and arequired transmission rate can be obtained by multiplying the perioddescribed in relation to FIG. 10 and the size described in FIG. 11.

When transmitting PTP by Ethernet, 01-80-C2-00-00-OE or01-1B-19-00-00-00 is used as the destination MAC address and 0x088F7 isused as the Ethertype. For the destination MAC address,01-80-C2-00-00-OE is used for messages such as PDelayReq, PDelayResp,PDelayRespFollowUp, etc., and 01:1B:19:00:00:00 is used for the othermessages (Announce, Sync, Follow_up, Delay_Req, Delay_Resp, etc.). Thisinformation can be used as a packet filter when setting up a PCCrule.

FIG. 12 illustrates an example of a UDP/IPv4 header according to anembodiment of the present disclosure.

Referring to FIG. 12, when the PTP is transmitted using UDP/IP, 28 bytesare increased compared to when the PTP is transmitted through Ethernet.That is, in the case of the PTP Sync message, when the PTP is configuredas two-step, it becomes 76+28 bytes, and when the PTP is configured asone-step, it becomes 118+28 bytes.

When transmitting the PTP using UDP/IPv4, 224.0.0.107 or 224.0.1.129 isused for the destination IP address, and 319 or 320 is used for the UDPdestination port. For the destination IP address, 224.0.0.107 is usedfor messages such as PDelayReq, PDelayResp, PDelayRespFollowUp, etc.,and 224.0.1.129 is used for the other messages (Announce, Sync,Follow_up, Delay_Req, Delay_Resp, etc.). On the other hand, depending onthe PTP domain, 224.0.1.129-224.0.1.132 are used instead of thedestination IP address of 224.0.1.129. For the UDP destination port, 319is used for the event messages such as Sync, DelayReq, PDelayReq,PDelayResp, etc., and 320 is used for the other PTP general messages(FollowUp, DelayResp, PDelayRespFollowUp, Announce, Management,Signaling, etc.). As such, it can be used as a packet filter whensetting up a PCCrule.

In case of transmitting PTP using UDP/IPv6, IPv6 header is 20 byteslonger than IPv4 header, so that in the case of the PTP Sync message,when the PTP is configured as two-step, it becomes 76+48 bytes, and whenthe PTP is configured as one-step, it becomes 118+48 bytes.

The case of transmitting the PTP using UDP/IPv6 is similar to the caseof transmitting the above-described UDP/IPv4. However,FF02:0:0:0:0:0:0:6B instead of 224.0.0.107 and FF0x:0:0:0:0:0:0:181instead of 224.0.1.129 are used as destination IP addresses. Thisinformation can be used as a packet filter when setting up a PCCrule.

FIG. 13 illustrates an example of a PTP profile according to anembodiment of the present disclosure.

Referring to FIG. 13, the PTP profile describes a profile name, anidentifier, a domain number of the corresponding PTP, a priority, and aBMCA type, and includes information indicating the type of clock used.In addition, a selection information for one-step or two-step, aninformation on a method to be used as a path delay mechanism, and aninformation on a method to be used as a transport mechanism aredesignated. In addition, an information on whether to use multicast orunicast, an address thereof, and an information on a period of each PTPmessage are included.

By using the address information used for multicast/unicast, it may beapplied as QoS rules and SDF filters, and the parameters of the QoS flowof FIG. 7 may be determined using one-step/two-step information, thepath delay mechanism, the delivery mechanism, the message rate (SyncRate, Delay Req/Resp Rate, Announce Rate), and the like. In someembodiments of the present disclosure, since the Announce message isless sensitive to the delivery time, it may be excluded from thecalculation of the parameter setting of the QoS flow, and delivered as aDefault QoS flow that is a Non-Guaranteed Bit Rate (Non-GBR).

When the UE provides the master clock, the UE or the AF has the PTPprofile, and when the TSN-DN provides the master clock, the SMF, thePCF, or the AF has the PTP profile. The PTP profile is information usedfor the configuration and operation of the PTP, and the UE, the SMF, thePCF, and the AF may use the PTP profile as it is to generate informationnecessary for creating the QoS flow when necessary, or convert it intoan information format required for creating the QoS flow formation andmanage it.

In addition, without receiving the PTP profile from the UE, the SMF maygenerate a PccRule capable of supporting the PTP profile required forthe TSC service through the DNN and the S-NSSAI. There may be two casesof receiving a session request including the PTP profile informationtogether with the DNN and the S-NSSAI from the UE, or receiving asession request including only the DNN and the S-NSSAI that does notinclude the PTP profile information from the UE, in each of these twocases, the SMF may determine the PCCrule itself (according to the storedTSC PTP information for the DNN/S-NSSAI), or the SMF may request the PCFto set the PCCrule. When the SMF requests the PCF to set PCCrule, indetermining the PCCrule, the PCF may determine the PCCrule according tothe information it stores (the TSC PTP information for the DNN/S-NSSAI)or the information from the AF or the UDM.

FIG. 14 illustrates obtaining a time synchronization protocol profileaccording to an embodiment of the present disclosure.

Referring to FIG. 14, acquiring a time synchronization protocol profileaccording to an embodiment of the present disclosure is performedthrough an Announce message. In the present disclosure, the timesynchronization protocol profile may use a method of presetting the timesynchronization protocol profile of the master clock to be used in theUE 100 to the UE 100, or may use a setting method of the UE 100 using anAnnounce message through the DS-TT 102. The method of presetting to theUE 100 is a method of setting the time synchronization protocol profileinformation of the master clock to be connected to the UE 100 to the UE100, and a setting method of the UE 100 using an Announce messagethrough the DS-TT 102 is possible through (A) or (B) of FIG. 14. In (A),the DS-TT 102 obtains the time synchronization protocol profile from theAnnounce message and provides it to the UE 100, and in (B), the UE 100obtains the time synchronization protocol profile from the Announcemessage.

Similarly, the method of setting the time synchronization protocolprofile in the network may use a method of setting the timesynchronization protocol profile in advance in any one of the SMF114/PCF 112/AF 110, or may a method of setting any one of the SMF114/PCF 112/AF 110 using the Announce message through NW-TT 106 is used.In (C) of FIG. 14, the time synchronization protocol profile of theAnnounce message received by NW-TT 106 is transferred to the SMF 114,the SMF 114 transfers it back to the PCF 112, and the PCF 112 transfersit to the AF 110 again.

FIG. 15 illustrates a relationship between QoS requirements of a masterclock profile according to an embodiment of the present disclosure.

Referring to FIG. 15, the illustrated is an embodiment of the settingrelationship of QoS requirements of the master clocks MC around the 5Gvirtual bridge 10. For convenience of explanation, the description willbe made based on the method of presetting, not the method of setting thetime synchronization protocol profile using the Announce message.

First, PtpPrf0 corresponding to the time synchronization protocolprofile of the master clock MC4 is set in advance.

When the UE1 100 a establishes a session for the TSC with PtpPrf_1corresponding to the time synchronization protocol profile of the masterclock MC1, the QoS flow for the time synchronization protocol to the UE1100 a is set based on the higher requirement among PtpPrf0 and PtpPrf_1.In this case, the time synchronization protocol profile for the set QoSflow may be referred to as PtpPrf0.

When the master clock MC2 is not connected to the UE2 yet, when the UE2100 b establishes a session for the TSC without an information on thetime synchronization protocol profile, the QoS flow for the timesynchronization protocol to the UE2 100 b is set based on therequirement of PtpPrf0. After the master clock MC2 is connected to theUE2 100 b, if the QoS requirement of the time synchronization protocolprofile of the master clock MC2 is higher than the requirement ofPtpPrf0, the UE2 100 b changes the session to set the QoS flow with thetime synchronization protocol profile PtpPrf_2 of the master clock MC2.Accordingly, the QoS flow for the time synchronization protocol of thesession to the UE1 100 a that has been previously set will also bechanged to the QoS flow that can satisfy the requirement of PtpPrf_2.

When the UE3 100 c establishes a session for the TSC with PtpPrf_3corresponding to the time synchronization protocol profile of the masterclock MC3, the QoS flow for the time synchronization protocol to the UE3100 c is set based on the PtpPrf_3 which is the higher requirement amongPtpPrf_2 and PtpPrf_3, and the QoS flows for the time synchronizationprotocol of the session to the UE1 100 a and the UE3 100 b that havebeen previously set will also be changed to the QoS flows that cansatisfy the requirement of PtpPrf_3.

Now, when the master clock MC5 with a higher level time synchronizationprotocol profile is connected to support the master clock MC5, the SMF114/PCF 112/AF 110 will change the QoS flow for supporting PtpPrf5,which is the time synchronization protocol profile of the master clockMC5, to a QoS flow that can satisfy the requirement of PtpPrf5 for thetime synchronization protocol of each session of UE1 100 a, UE2 100 b,and UE3 100 c.

The above example is an example of setting a QoS flow based on a higherrequirement of the time synchronization protocol profile. When multiplemaster clocks compete, the master clock is determined through the BMCA,and in this case, the master clock is selected based on the priority,the clock class, and the clock accuracy, etc. of each clock to be themaster clock. In the above example, comparing the time synchronizationprotocol profile is to compare the profile when it is selected as themaster clock through the BMCA based on the priority, the clock class,the clock accuracy, etc. Here, BMCA includes all of a method ofselecting a master clock for each port by being distributed from eachclock using an Announce message, and a centralized method in which theconnected clock information is transmitted to the SMF 114/PCF 112/AF 110and compared.

FIG. 16 illustrates a procedure for setting a QoS flow for a timesynchronization protocol when establishing a PDU session according to anembodiment of the present disclosure.

Referring to FIG. 16, in step 1, when the UE_n 100, which is anarbitrary n-th UE, establishes a session, a DNN and a S-NSSAIinformation for the TSC service are included in the PDU SessionEstablish Request. In this case, the ID of the session to be establishedand a PTP profile (PtpPrf_n of UE_n 100) information may be includedtogether. The PTP profile is an information of the master clock to betransmitted from the UE 100 and is provided to the UE 100 through theDS-TT or the like. The time synchronization protocol profile for themaster clock may be preset in the UE 100 for storage and management, orthe UE 100 may store/manage the time synchronization protocol profileincluded in the Announce message received through DS-TT.

In step 3, the PDU Session Establish Request from the UE 100 istransferred to the SMF 114, and in step 7, the SMF 114 sets the policyof the session for the received PDU Session Establish Request. In thiscase, a predefined PCCrule (policy and charging control rule) preset inthe SMF 114 may be used. This is a PCCrule that includes the QoSinformation and the packet filter information that can support the PTPprofile of the DNN and the S-NSSAI that provides TSC, based on the DNNand the S-NSSAI information, it can be known that the service to the DNNand the S-NSSAI requires the TSC (preset), a QoS information (preset)for the PTP for the corresponding TSC and a packet filter information(preset) for the PTP for the TSC may be determined.

Alternatively, in step 7-1, the SMF 114 may request the PCF 112 to set adynamic PCCrule. In this case, the SMF 114 may transmit the DNN, theS-NSSAI, the session ID, and the PTP profile information included in thePDU Session Establish Request received from the UE 100 together, and theSMF 114 allows the PCF 112 to use it to set the PCCrule as in step 7-2.This is a PCCrule that includes the QoS information and the packetfilter information that can support the PTP profile of the DNN and theS-NSSAI that provides TSC, based on the DNN and the S-NSSAI information,it can be known that the service to the DNN and the S-NSSAI requires theTSC (preset a), a QoS information (preset b) for the PTP for thecorresponding TSC and a packet filter information (preset c) for the PTPfor the TSC may be determined, and the PCF may set the above preset (a,b, c) information in advance internally or may be acquired through AF orUDM and the like.

In step 7-3, the PCF 112 transmits the set PCCrule to the SMF 114.

Referring to step 7-4, the PCF 112 may set the PCCrule by itself, but byrequesting the AF for authorization for the service to be provided tothe UE 100, the PCF 112 may receive a service information for acorresponding service from the AF and apply it to PCCrule creation. Inthis case, the PCF 112 transmits the DNN, the S-NSSAI, the session ID,and the PTP profile information to the AF together, and receivesinformation necessary for PCCrule setting from the AF.

When the PTP profile from the UE 100 is not provided, the PCF 112creates a PCCrule by referring to the time synchronization protocolprofile of the corresponding DN and the TSN domain provided by the DNthrough the DNN, the S-NSSAI, and the TSN domain.

The time synchronization protocol profile PtpPrf0 of the TSN DNspecified by one or more of the DNN, the S-NSSAI, and the TSN domain maybe stored and managed in the SMF 114/PCF 112/AF in advance. PtpPrf0 canbe managed as a preset value, and the SMF 114/PCF 112/AF maystore/manage the time synchronization protocol profile included in theAnnounce message received by the UPF 104 (NW-TT).

PCCrule may include information necessary to set up a QoS flow for atime synchronization protocol.

Meanwhile, if the PTP profile from the UE 100 is lower than the QoSrequirement of PtpPrf0, a QoS flow may be created based on PtpPrf0.

In step 7-3 and below of FIG. 16, one or more QoS flows indicating thecorresponding QoS flows are denoted by QFI. The QFI indicates attributeinformations of each QoS flow as shown in FIG. 7. As the QoS flow forthe time synchronization protocol, the uplink/downlink QoS flow is setrespectively.

The SMF 114 determines the QoS flow by the SMF 114 itself in step 7, ordetermines the QoS flow based on the PCCrule received from the PCF 112,and then transmits the information to the UPF 104/RAN 108/UE 100. Inaddition, the PCF 112 creates a PCCrule based on the DNN, the S-NSSAI,and the TSN domain included in the UE profile received from the SMF 114,so that the SMF 114 creates a QoS flow. Also, the PCF 112 may requestauthorization of a service including a PTP profile when requestingservice information to the AF. Alternatively, when the PTP profile isnot included in the service information request of the PCF 112, the AFmay provide service information on the service provided to the UE 100 tothe PCF 112.

In step 10, the corresponding QoS flow and the SDF filter informationfor the QoS flow are provided to the UPF 104, and the QoS flow for thedownlink from the UPF 104 to the RAN 108 is set to the UPF 104.

In step 16, the QoS flow for the uplink from the RAN 108 to the UPF 104is set to the UPF 104.

In steps 11 and 12, the SMF 114 provides setting information of the QoSflow for the session to the RAN 108 through the AMF 116, and alsoprovides the QoS rule to the UE 100 through a PDU session establishaccept. This QoS rule includes a PacketFilter (i.e., a QoSRule filter)that can set a QoS flow for a time synchronization protocol and QoSparameters required therefor, and map time synchronization messages tothe QoS flow.

Step 13 represents that PDU session establish accept information fromthe SMF 114 to the UE 100 is transferred from the RAN 108 to the UE 100.A response from the UE 100 is transmitted to the SMF 114 through steps13, 14, and 15, and the SMF 114 receives downlink information of thecorresponding QoS flow from the RAN 108 and sets it to the UPF 104 instep 16.

FIG. 17 illustrates a procedure for modifying a QoS flow through a PDUsession modification procedure from a UE according to an embodiment ofthe present disclosure.

Referring to FIG. 17, when the QoS flow set in FIG. 16 cannot satisfyPtpPrf_n of the UE_n 100 or when the QoS requirement of the master clockto be transmitted from the UE 100 increases, the UE 100 may request aQoS flow modification through a session modification procedure. In thiscase, the QoS flow may be specified as a QoS flow having PktFltr for atime synchronization message among the PktFltr received by the UE 100 instep 13 of FIG. 16.

In step 1, the UE 100 requests a session modification including ReQQoS,which is a required QoS, for a QoS flow that can be specified by thePktFltr, which is Packet Filter for a time synchronization message. Inthis case, the UE 100 may request a session modification by includingPtpPrf_n to be transmitted.

In step 3, the PDU Session Modify Request from the UE 100 is transmittedto the SMF 114 through the step 3, and the SMF 114 sets the sessionpolicy for the received PDU Session Modify Request. At this time, apredefined PCCrule (policy and charging control rule) preset in the SMF114 may be used, or the PCF 112 may be requested to change the dynamicPCCrule in step 7-1. In this case, the SMF 114 may transmit the sessionID, the PktFltr, the ReQQoS, and the PtpPrf_n information included inthe PDU Session Modify Request received from the UE 100 together, andthe SMF 114 allows the PCF 112 to use it to change the PCCrule as instep 7-2.

In step 7-3, the PCF 112 transmits the changed PCCrule to the SMF 114.

Referring to step 7-4, the PCF 112 may change the PCCrule by itself, butby requesting the AF for authorization for the service to be provided tothe UE 100, the PCF 112 may receive a service information for acorresponding service from the AF and apply it to PCCrule creation. Inthis case, the PCF 112 transmits the session ID, the PktFltr, theReQQoS, and the PtpPrf_n information together, and receives informationnecessary for PCCrule setting from the AF.

The SMF 114/PCF 112/AF can be selectively use among the ReQQoS and thePtpPrf_n.

When the ReQQoS and the PtpPrf_n from the UE 100 are higher than the QoSrequirement of the PtpPrf0 currently used in the TSN domain to which theUE 100 belongs, the session modification procedure of FIG. 18 must beperformed for the sessions of other UEs using the QoS flow based on thePtpPrf0 currently used in the TSN domain.

The SMF 114 determines the modification of the QoS flow by the SMF 114itself in step 7, or determines the QoS flow based on the PCCrulereceived from the PCF 112, and then transmits the information to the UPF104/RAN 108/UE 100. In addition, the PCF 112 creates a PCCrule based onthe session ID, the PktFltr, the ReQQoS, the PtpPrf_n and the TSN domainand the like, received from the SMF 114, so that the SMF 114 modifies aQoS flow. Also, the PCF 112 may request authorization of a serviceincluding a PTP profile when requesting service information to the AF.

In any one of steps 10, 16, and 19, the SMF 114 requests the UPF 104 tomodify the QoS flow.

In steps 11 and 12, the SMF 114 provides modification information of theQoS flow for the session to the RAN 108 through the AMF 116, and alsoprovides the QoS rule to the UE 100 through a PDU session modifycommand. This QoS rule includes a PacketFilter that can modify a QoSflow for a time synchronization protocol, and map time synchronizationmessages to the QoS flow.

Step 13 represents that PDU session modification command informationfrom the SMF 114 to the UE 100 is transferred from the RAN 108 to the UE100.

The response from the RAN 108 is transmitted to the SMF 114 throughsteps 14 and 15, and the response from the UE 100 is transmitted to theSMF 114 through steps 17 and 18.

FIG. 18 illustrates a procedure for modifying a QoS flow for an existingtime synchronization protocol of another UE using a PDU sessionmodification procedure according to an embodiment of the presentdisclosure.

Referring to FIG. 18, FIG. 18 is a case in which the SMF 114/PCF 112/AFdetects a PTP profile having a higher requirement than the QoSrequirement of PtpPrf0 currently being used for the corresponding TSNdomain. FIG. 18 shows a procedure for modifying the QoS flow for thetime synchronization protocol of each UE 100 being used by the SMF114/PCF 112/AF for the TSN domain, in the case where the PtpPrf_n or theReQQoS received from any n-th UE 100 is higher than the QoS requirementof the PtpPrf0 currently being used for the TSN domain, or in the casewhere the time synchronization protocol profile to be provided by thenetwork is higher than the QoS requirement of the PtpPrf0 being used forthe TSN domain. This means that the UE1 is doing a service by settingPtpPrf0 of a certain level, but when a higher level PTP needs to beserviced due to other circumstances of the UE2 or the network, the UE1also needs to change the setting to its higher level PtpPrf_n, FIG. 19may be referred to.

In step 7-2, when the ReQQoS and the PtpPrf_n from the UE 100 are higherthan the QoS requirement of the PtpPrf0 currently used in the TSN domainto which the UE 100 belongs, the PCF 112 detects the need to modify theQoS flow for the sessions of other UEs using the QoS flow based on thePtpPrf0 currently used in the TSN domain, and modifies the PCCrule foreach UE's session and informs the SMF 114 through step 7-1.

Change of PCCrule of PCF 112 is performed directly by PCF 112 or bynotifying AF that PtpPrf_n of UE_n 100 is higher than existing QoS,service information related to change of PCCrule can be received fromAF.

In step 7-1, after the PCF 112 notifies the SMF 114 of the PCCrulechange, steps 10 to 19 are the same as described with reference to FIG.17. However, it is applied to each of the QoS flows of each UE in thecorresponding TSN domain.

FIG. 19 illustrates a procedure for setting a QoS flow for a PDU sessiontime synchronization protocol according to an embodiment of the presentdisclosure.

Referring to FIG. 19, FIG. 19 shows an overall flow in the 5GS forsetting a QoS flow for time synchronization of a PDU session. In stepS001, any one or more of the SMF/PCF/AF set the PTP profilecorresponding to the DNN, the S-NSSAI, and the TSN domains as PtpProf0.In step S003, a SsnEstb, which is session establishment, request isreceived from an arbitrary UE, and in step S003-1, determines whetherQoS flow setting is necessary for the TSC based on the DNN, the S-NSSAIand the PTP profile. At this time, in step S003-2, if there is no needto set the QoS flow for the time synchronization protocol based on theDNN and the S-NSSAI received through AMF, any one of SMF/PCF/AF sets theNon-GBR default QoS flow, and proceeds to step S00A.

In step S005, in the case of the TSC requiring the setting of a QoS flowfor the time synchronization protocol, it is checked whether the PTPprofile is included in the session establishment request message fromthe UE, and if the PTP profile is not included, a QoS flow is set withPtpPrf0 of the corresponding TSN domain in step S011. At this time, theset QoS flow can be set as a separate QoS flow, or the default QoS flowcan be set by applying GBR instead of Non-GBR, or higher QoS.

If the PTP profile is included and the PTP profile from the UE(PtpPrf_n, which is the PTP profile from the nth UE, UE_n) has lowerrequirements than the existing PTP profile PtpPrf0 in step S009, a QoSflow of PtpPrf0 level is set in step S011.

If PtpPrf_n from the UE has a higher requirement than PtpPrf0, which isthe existing PtpProfile, in step S009, a QoS flow of PtpPrf_n level isset during the session establishment procedure in step S103, the QoSflow in the PDU sessions of other UEs that are previously set using thetime synchronization protocol together is changed to the level ofPtpPrf_n in step S115, and PtpPrf0 is changed to PtpPrf_n in step S117.Steps S011 and S013 are also described in FIG. 16, and step S115 is alsodescribed in FIG. 17.

On the other hand, in response to the session modification request fromthe UE in step S203, it is checked whether the corresponding session isTSC in step S203-1, and in the case of a non-TSC session, the QoS flowis modified in a conventional manner in response to the UE's sessionmodification request in step S203-2.

In step S209, when the QoS parameter (QosPara_n) or PtpPrf_n of the QoSflow of the UE's session modification request is higher than the currentPtpPrf0 or the corresponding QoS parameter (QosPara_n(t−1), the previousQoS flow parameter of UE_n), in step S213, the QoS parameters of the QoSflow for the time synchronization protocol of the UE are modified duringthe session modification (SsnMod) procedure. Also, in step S115, the QoSflow in the PDU sessions of other UEs that are previously set using thetime synchronization protocol of the same TSN domain is changed to thelevel of PtpPrf_n, and in step S117, PtpPrf0 is changed to PtpPrf_n.

FIG. 20 is a block diagram illustrating a computing device according toan embodiment of the present disclosure.

Referring to FIG. 20, a computing device 50 may be a network entity of a5G system, for example, UE 100, DS-TT 102, UPF 104, NW-TT 106, RAN 108,TSN AF 110, PCF 112, SMF 114, AMF 116, UDM 118 and NEF 120, and thelike. Also, a method of creating a QoS flow for a time synchronizationprotocol in a wireless communication network according to embodiments ofthe present disclosure may be implemented using the computing device 50.

The computing device 50 includes at least one of a processor 510, amemory 530, a user interface input device 540, a user interface outputdevice 550, and a storage device 560 communicating through a bus 520.The computing device 50 may also include a network 40, such as a networkinterface 570 that is electrically connected to a wireless network. Thenetwork interface 570 may transmit or receive signals with otherentities through the network 40.

The processor 510 may be implemented in various types such as anapplication processor (AP), a central processing unit (CPU), and agraphic processing unit (GPU), and may be any semiconductor device whichexecutes instructions stored in the memory 530 or the storage device560. The processor 510 may be configured to implement the functions andmethods described in FIG. 1 to FIG. 19.

The memory 530 and the storage device 560 may include various types ofvolatile or nonvolatile storage media. For example, the memory mayinclude read-only memory (ROM) 531 and random access memory (RAM) 532.In an embodiment of the present disclosure, the memory 530 may belocated inside or outside the processor 510, and the memory 530 may beconnected to the processor 510 through various known means.

In addition, at least some of a method of creating a QoS flow for a timesynchronization protocol in a wireless communication network accordingto embodiments of the present disclosure may be implemented as a programor software executed on the computing device 50, and the program orsoftware may be stored in a computer-readable medium.

In addition, at least some of a method of creating a QoS flow for a timesynchronization protocol in a wireless communication network accordingto embodiments of the present disclosure may be implemented withhardware that can be electrically connected to the computing device 50.

According to the embodiments of the present disclosure described so far,by creating a QoS flow reflecting the PTP profile of the timesynchronization protocol, and by allowing the time synchronizationprotocol to be processed as the corresponding QoS flow, the timesynchronization quality is guaranteed and TSC can be smoothly provided.

The components described in the example embodiments may be implementedby hardware components including, for example, at least one digitalsignal processor (DSP), a processor, a controller, anapplication-specific integrated circuit (ASIC), a programmable logicelement, such as an FPGA, other electronic devices, or combinationsthereof. At least some of the functions or the processes described inthe example embodiments may be implemented by software, and the softwaremay be recorded on a recording medium. The components, the functions,and the processes described in the example embodiments may beimplemented by a combination of hardware and software.

The method according to example embodiments may be embodied as a programthat is executable by a computer, and may be implemented as variousrecording media such as a magnetic storage medium, an optical readingmedium, and a digital storage medium.

Various techniques described herein may be implemented as digitalelectronic circuitry, or as computer hardware, firmware, software, orcombinations thereof. The techniques may be implemented as a computerprogram product, i.e., a computer program tangibly embodied in aninformation carrier, e.g., in a machine-readable storage device (forexample, a computer-readable medium) or in a propagated signal forprocessing by, or to control an operation of a data processingapparatus, e.g., a programmable processor, a computer, or multiplecomputers. A computer program(s) may be written in any form of aprogramming language, including compiled or interpreted languages andmay be deployed in any form including a stand-alone program or a module,a component, a subroutine, or other units suitable for use in acomputing environment. A computer program may be deployed to be executedon one computer or on multiple computers at one site or distributedacross multiple sites and interconnected by a communication network.

Processors suitable for execution of a computer program include, by wayof example, both general and special purpose microprocessors, and anyone or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer may include atleast one processor to execute instructions and one or more memorydevices to store instructions and data. Generally, a computer will alsoinclude or be coupled to receive data from, transfer data to, or performboth on one or more mass storage devices to store data, e.g., magnetic,magneto-optical disks, or optical disks. Examples of informationcarriers suitable for embodying computer program instructions and datainclude semiconductor memory devices, for example, magnetic media suchas a hard disk, a floppy disk, and a magnetic tape, optical media suchas a compact disk read only memory (CD-ROM), a digital video disk (DVD),etc. and magneto-optical media such as a floptical disk, and a read onlymemory (ROM), a random access memory (RAM), a flash memory, an erasableprogrammable ROM (EPROM), and an electrically erasable programmable ROM(EEPROM) and any other known computer readable medium. A processor and amemory may be supplemented by, or integrated into, a special purposelogic circuit.

The processor may run an operating system (OS) and one or more softwareapplications that run on the OS. The processor device also may access,store, manipulate, process, and create data in response to execution ofthe software. For purpose of simplicity, the description of a processordevice is used as singular; however, one skilled in the art will beappreciated that a processor device may include multiple processingelements and/or multiple types of processing elements. For example, aprocessor device may include multiple processors or a processor and acontroller. In addition, different processing configurations arepossible, such as parallel processors.

Also, non-transitory computer-readable media may be any available mediathat may be accessed by a computer, and may include both computerstorage media and transmission media.

The present specification includes details of a number of specificimplements, but it should be understood that the details do not limitany invention or what is claimable in the specification but ratherdescribe features of the specific example embodiment. Features describedin the specification in the context of individual example embodimentsmay be implemented as a combination in a single example embodiment. Incontrast, various features described in the specification in the contextof a single example embodiment may be implemented in multiple exampleembodiments individually or in an appropriate sub-combination.Furthermore, the features may operate in a specific combination and maybe initially described as claimed in the combination, but one or morefeatures may be excluded from the claimed combination in some cases, andthe claimed combination may be changed into a sub-combination or amodification of a sub-combination.

Similarly, even though operations are described in a specific order onthe drawings, it should not be understood as the operations needing tobe performed in the specific order or in sequence to obtain desiredresults or as all the operations needing to be performed. In a specificcase, multitasking and parallel processing may be advantageous. Inaddition, it should not be understood as requiring a separation ofvarious apparatus components in the above described example embodimentsin all example embodiments, and it should be understood that theabove-described program components and apparatuses may be incorporatedinto a single software product or may be packaged in multiple softwareproducts.

While this disclosure has been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the disclosure is not limited to the disclosedembodiments. On the contrary, it is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

What is claimed is:
 1. A method of creating a QoS flow for a timesynchronization protocol in a wireless communication network, the methodcomprising: receiving, by a Session Management Function (SMF), a PTPprofile information from a UE, together with at least one of a DNN, aS-NSSAI information and a session ID for a Time Sensitive Communication(TSC) service; setting, by the SMF, a PCCrule of the QoS flow for thetime synchronization protocol; providing, by the SMF, the QoS flow andan SDF filter information for the QoS flow to a User Plane Function(UPF); and providing, by the SMF, the QoS flow and a QoS rule filter toan Access and Mobility Management Function (AMF).
 2. The method of claim1, wherein: the setting, by the SMF, a PCCrule of the QoS flow for thetime synchronization protocol, comprises: using a preset PCCrule,setting, by the SMF, the PCCrule and the QoS flow for the timesynchronization protocol.
 3. The method of claim 1, wherein: thesetting, by the SMF, a PCCrule of the QoS flow for the timesynchronization protocol, comprises: requesting, by the SMF, a PolicyControl Function (PCF) to set a PCCrule; receiving the set PCCrule fromthe PCF; and using the received PCCrule, setting, by the SMF, thePCCrule and the QoS flow for the time synchronization protocol.
 4. Themethod of claim 1, wherein: the requesting, by the SMF, a PCF to set aPCCrule, comprises: transmitting, by the SMF, the PTP profileinformation provided from the UE to the PCF together with the DNN, theS-NSSAI information and the session ID.
 5. The method of claim 1,wherein: the PTP profile information is transmitted through an Announcemessage.
 6. The method of claim 1, wherein: the PTP profile informationcomprises: at least one of a selection information for one-step ortwo-step, an information on a method to be used as a path delaymechanism and an information on a method to be used as a transportmechanism, an information on whether to use multicast or unicast, itsaddress, and an information on the period of each PTP message.
 7. Themethod of claim 1, wherein: the QoS flow comprises: at least one ofPacket Delay Budget (PDB), Priority, Allocation and Retention Priority(ARP), and Guaranteed Flow Bit Rate (GFBR).
 8. The method of claim 1,wherein: the SDF filter and the QoS rule filter comprises: at least oneof a multicast address of an Ethernet for the time synchronizationprotocol, an ethertype of the Ethernet for the time synchronizationprotocol, a multicast address of IP for time synchronization protocoland a port of UDP for time synchronization protocol.
 9. The method ofclaim 1, wherein: when a QoS requirement of a PTP profile informationprovided from the UE is lower than a QoS requirement for the preset PTPprofile, the QoS flow is created based on the QoS requirement for thepreset PTP profile.
 10. A network entity of a 5G system operating as aTSN bridge, the network entity comprising: a network interface; and aprocessor configured to: receive a PTP profile information from a UE,together with at least one of a DNN, a S-NSSAI information and a sessionID for a TSC service; setting a PCCrule of the QoS flow for the timesynchronization protocol; providing the QoS flow and an SDF filterinformation for the QoS flow to a UPF; and providing the QoS flow and aQoS rule filter to an AMF.
 11. A method of creating a QoS flow for atime synchronization protocol in a wireless communication network, themethod comprising: receiving, by a SMF, a session modification requestcomprising ReQQoS, which is a QoS required for the QoS flow specified byPktFltr, which is Packet Filter for the time synchronization message,from a UE; setting, by the SMF, a session policy; requesting, by theSMF, a QoS flow modification for the session to the UPF; and providing,by the SMF, a QoS flow modification information for the session to anAMF.
 12. The method of claim 11, wherein: the setting, by the SMF, asession policy, comprises: using a preset PCCrule, setting, by the SMF,the session policy.
 13. The method of claim 11, wherein: the setting, bythe SMF, a session policy, comprises: requesting, by the SMF, the PCF tomodify the PCCrule; receiving the modified PCCrule from the PCF; andusing the received PCCrule, setting, by the SMF, the session policy. 14.The method of claim 11, further comprising: when the ReQQoS and the PTPprofile from the UE are higher than a QoS requirement of a PTP profilecurrently used in a TSN domain to which the UE belongs, performing asession modification for the sessions of other UEs using a QoS flowbased on the PTP profile currently used in the TSN domain.
 15. Themethod of claim 11, wherein: the PTP profile information comprises: atleast one of a selection information for one-step or two-step, aninformation on a method to be used as a path delay mechanism and aninformation on a method to be used as a transport mechanism, aninformation on whether to use multicast or unicast, its address, and aninformation on the period of each PTP message.
 16. A network entity of a5G system operating as a TSN bridge, the network entity comprising: anetwork interface; and a processor configured to: receive a sessionmodification request comprising ReQQoS, which is a QoS required for theQoS flow specified by PktFltr, which is Packet Filter for the timesynchronization message, from a UE; setting a session policy; requestinga QoS flow modification for the session to the UPF; and providing a QoSflow modification information for the session to an AMF.
 17. A method ofcreating a QoS flow for a time synchronization protocol in a wirelesscommunication network, the method comprising: receiving, by a SMF, atleast one of a DNN, a S-NSSAI information and a session ID for a TSCservice not including a PTP profile information from a UE; setting, bythe SMF, a PCCrule of the QoS flow for the time synchronization protocolusing a PTP profile information stored in the SMF; providing, by theSMF, the QoS flow and an SDF filter information for the QoS flow to aUPF; and providing, by the SMF, the QoS flow and a QoS rule filter to anAMF.
 18. A network entity of a 5G system operating as a TSN bridge, thenetwork entity comprising: a network interface; and a processorconfigured to: receive at least one of a DNN, a S-NSSAI information anda session ID for a TSC service not including a PTP profile informationfrom a UE; setting a PCCrule of the QoS flow for the timesynchronization protocol using a PTP profile information stored in thenetwork entity; providing, by the network, the PCCrule to the SMF;providing, by the SMF, the QoS flow and an SDF filter information forthe QoS flow to a UPF; and providing, by the SMF, the QoS flow and a QoSrule filter to an AMF.